Electronic Leak Detectors

CAUTION: CARE SHOULD BE TAKEN TO PREVENT PERSONAL INJURY WHICH COULD OCCUR DUE TO TOUCHING A HOT ENGINE WHEN TESTING. TESTS SHOULD BE DONE WITH THE ENGINE OFF AND AS COOL AS POSSIBLE. DO NOT OPERATE THE DETECTOR IN A COMBUSTIBLE ATMOSPHERE SINCE ITS SENSOR OPERATES AT A HIGH TEMPERATURE.





The successful use of this and any other electronic leak detector depends greatly upon the scan rate and carefully following the manufacturer's instructions regarding calibration, operation and maintenance. Each joint, including soldered, brazed and welded areas, must be circled moving at 25-30 mm (1-2 in.) per second with the tip of the probe as close to the surface as possible. The tip should be no more than 6.35 mm (1/4 in.) away and must not block air intake. A leak is indicated when the audible tone goes from a steady one to two clicks per second to a solid alarm. The balance knob should be adjusted frequently to maintain the one to two clicks per second.

ELECTRONIC LEAK TESTING OF FITTINGS AND CONNECTIONS





1. Install a R134a manifold gauge set to determine if refrigerant is present in the system. If no pressure is indicated, charge system with 0.50 kg (1 lb.) of refrigerant.
(1) Low side service ports.
(2) High side service ports.





2. Position probe of electronic leak detector to discharge hose fittings:
a. Move probe 025-50 mm (1-2 in.) per second around connection to compressor making sure air is able to flow past the tip.
b. Move probe to service valve on discharge hose. Circle service valve.
c. Check other possible sources of a refrigerant leak along hose.
3. Position probe of electronic leak detector to suction hose fittings:
a. Move probe 025-50 mm (1-2 in.) per second around connection to compressor making sure air is able to flow past tip.
b. Move probe to service valve on suction hose. Circle the service valve.
c. Check other possible sources of a refrigerant leak along hose.





4. Position probe (1) of electronic leak detector to condenser inlet fitting.
5. Move probe along aluminum fins of condenser and tubes within the fins. Cover all soldered, brazed and welded areas.





6. Position probe (1) of electronic leak detector to condenser outlet fitting.
7. Move probe along receiver-dehydrator hose assembly.
8. Position probe on top of receiver-dehydrator.
9. Position probe to receiver-dehydrator and liquid line connection.





10. Position probe (1) to pressure sensor.





11. Position probe (1) to liquid line connection at thermal expansion valve (TXV).
12. Circle entire area of thermal expansion valve including the rear portion that contacts cowl (engine side of front of dash).





13. Circle compressor clutch area with probe Olin front and back.

IMPORTANT: Turn on blower fan for at least 15 seconds before removing the blower motor assembly. Wait 10 minutes before leak checking evaporator. This step will reduce the chance of misdiagnosis of evaporator due to other possible contaminates in evaporator area that might trigger electronic leak detector.





IMPORTANT: Steps 14 and 15 pertain to left hand drive vehicles only. If procedure is being performed on a right-hand drive vehicle, skip steps 14 and 15 and proceed with steps 16 and 17.

14. Check evaporator leak:
a. Disconnect blower motor electrical connector.
b. Remove blower motor mounting screws.
c. Remove blower motor and cover.
d. Position probe (1) inside of blower motor housing.
e. Point probe towards left side of vehicle or driver's position (the evaporator is to the left of the blower motor housing).





15. After evaporator leak check is complete, replace blower motor:
a. Install blower motor and cover.
b. Install blower motor mounting screws.
c. Install electrical connector to blower motor.





16. Check evaporator leak: (POSTAL VEHICLES ONLY)
a. Disconnect blower motor resistor electrical connector.
b. Remove blower motor resistor mounting screws.
c. Remove blower motor resistor.
d. Position probe inside of blower motor housing.
e. Point probe towards right side of vehicle or driver's position (the evaporator is to the right of the blower motor housing).





17. After evaporator leak check is complete, replace blower motor resistor:
a. Install blower motor resistor.
b. Install blower motor resistor mounting screws.
c. Install electrical connector to blower motor resistor.
18. If the above procedures have not identified a refrigerant leak and you still suspect there is one, recheck the above connections. Additionally, check path along entire routing of A/C components with electronic detector for nicked or damaged hoses, fittings, bends in tubing and corrosion under protective tubing. Check any hidden areas such as the receiver-dehydrator routing.